CN109642145B - Sealing material composition, liquid crystal cell, and method for producing liquid crystal cell - Google Patents

Abstract

Translated fromChinese

为了提供一种在用于扫描天线等的液晶单元中抑制电压保持率的降低的密封材料组成物等，本发明的密封材料组成物具备：光自由基聚合引发剂，若经具有450nm以上的波长的光照射则产生自由基；及聚合成分，包含利用自由基而能够聚合的聚合性官能基。

In order to provide a sealing material composition or the like that suppresses a decrease in voltage holding ratio in a liquid crystal cell used for a scanning antenna or the like, the sealing material composition of the present invention includes: a photoradical polymerization initiator, which has a wavelength of 450 nm or more The light irradiation generates free radicals; and the polymerization component includes a polymerizable functional group that can be polymerized by using the free radicals.

Description

Sealing material composition, liquid crystal cell, and method for producing liquid crystal cell

Technical Field

The present invention relates to a sealing material composition, a liquid crystal cell, and a method for manufacturing a liquid crystal cell.

Background

An antenna used for mobile communication, satellite broadcasting, or the like requires a beam scanning function capable of changing a beam direction. As an antenna having such a function, a scanning antenna using large dielectric anisotropy (birefringence) of a liquid crystal material (including nematic liquid crystal and polymer dispersed liquid crystal) has been proposed (for example,patent documents 1 to 3). Such a scanning antenna has a structure in which a liquid crystal layer is sandwiched between a pair of substrates with electrodes (i.e., a liquid crystal cell for a scanning antenna).

Documents of the prior art

Non-patent document

[ patent document 1] Japanese patent application laid-open No. 2013-539949

[ patent document 2] Japanese patent laid-open publication No. 2016-512408

[ patent document 3] Japanese patent application laid-open No. 2009-538565

Disclosure of Invention

Technical problem to be solved by the invention

In the scanning antenna, a liquid crystal compound having a sufficient level of dielectric anisotropy (Δ ∈) in the gigahertz band is required. Therefore, the use of a isothiocyanate group-containing liquid crystal compound having high dielectric anisotropy is essentially indispensable as a liquid crystal compound for a scanning antenna.

However, a liquid crystal compound containing an isothiocyanate group has a property of being weak against light (ultraviolet light, visible light, or the like). Therefore, for example, in a method for manufacturing a liquid crystal cell including a step of applying a liquid crystal material by an ODF (One drop fill) method, when light (for example, ultraviolet light) is applied to an uncured frame-shaped sealing material (sealing material composition) formed on a substrate before bonding, a part of the light is applied to a liquid crystal material (a liquid crystal compound containing an isothiocyanate group, or the like) located inside the frame-shaped sealing material, and a part of the liquid crystal material is deteriorated. As a result, the photoreactive product of the isothiocyanate group-containing liquid crystal compound may significantly reduce the Voltage Holding Ratio (VHR) between the substrates of the liquid crystal cell. If the voltage holding ratio is lowered, the scanning antenna operates poorly, which is problematic.

Here, the mechanism of forming impurities from a liquid crystal compound containing an isothiocyanate group in a liquid crystal cell, which causes a decrease in voltage holding ratio, will be described with reference to fig. 1. FIG. 1 is an explanatory view showing a mechanism of forming an impurity containing a stable free radical from a liquid crystal compound containing an isothiocyanate group. As shown in FIG. 1, the isothiocyanate group-containing liquid crystal compound represented by the formula (a-1) has a structure in which an isothiocyanate group is bonded to a phenylene group (-C)₆H₄-N＝C ═ S), and this isothiocyanate group is easily combined with moisture (H) permeating from the outside of the liquid crystal cell₂O), or a functional group having active hydrogen (e.g., carboxyl group, hydroxyl group, etc.) present in the periphery. As a result of this reaction, a compound having a thiourethane bond or a compound having another bond (-C) as shown in the formula (a-2) is formed from a liquid crystal compound having an isothiocyanate group₆H₄-NH-CS-O-). These bonds are easily cleaved (photocleaved) when irradiated with light, and form a group of compounds each containing a radical as shown in chemical formula (a-3) and chemical formula (a-4).

Among these compounds, the compound represented by the formula (a-3) is particularly easily reacted with oxygen. When the chemical formula (a-3) is oxidized, a compound containing a stable radical with high activity (the compound represented by the chemical formula (a-5)) is formed. Since such radicals are hard to disappear in the liquid crystal layer, the probability of generating ion components in the liquid crystal layer due to the radicals is high, and the voltage holding ratio of the liquid crystal cell is lowered.

In addition, a liquid crystal compound containing an isothiocyanate group generally has a structure in which a plurality of phenylene groups are linked. The larger the number of phenylene groups, the more easily light absorption occurs in a long wavelength region (light of 350nm or more or 400nm or more). Further, when a tolan group is contained between a plurality of phenylene groups, it is easier to absorb light having a long wavelength (400nm or more or 420nm or more), and radical formation by photocleavage of the thiourethane bond or the like and oxidation reaction of the formed radical are easily caused.

Disclosure of Invention

The invention aims to provide a sealing material composition and the like for inhibiting the reduction of voltage holding ratio in a liquid crystal cell used for a scanning antenna and the like.

Means for solving the problems

The sealing material composition of the present invention comprises: a photo-radical polymerization initiator that generates radicals when irradiated with light having a wavelength of 450nm or more; and a polymerization component containing a polymerizable functional group polymerizable by a radical.

In the sealing material composition, the photo radical polymerization initiator preferably has a structure represented by the following chemical formula (1).

[ solution 1]

In the chemical formula (1), R represents a substituent bonded to an arbitrary position of the benzene ring.

In the sealant composition, it is preferable that R is composed of a polymerizable functional group represented by the following chemical formula (2).

[ solution 2]

-A¹-B¹ (2)

In the chemical formula (2), A¹Represents a linear, branched or cyclic alkylene group having 1 to 6 carbon atoms, an alkyleneoxy group or a direct bond, B¹Represents an acryloyloxy group, a methacryloyloxy group, an acryloylamino group or a methacryloylamino group.

In the sealant composition, the photo radical polymerization initiator having the polymerizable functional group may be composed of a compound represented by the following chemical formula (3).

[ solution 3]

In the chemical formula (3), n is 0 or 1, Ar represents an arylene group, and the H atom of each functional group may be substituted with an alkyl group, a halogen group, a hydroxyl group or an alkoxy group. In addition, A²And A¹Independently of each other, represents a linear, branched or cyclic alkylene group, alkyleneoxy group or a direct bond having 1 to 6 carbon atoms, B²And B¹Independently of one another, represents acryloyloxy, methacryloyloxy, acryloylamino or methacryloylamino.

In the sealant composition, the photo radical polymerization initiator having the polymerizable functional group may be composed of a compound represented by the following chemical formula (4).

[ solution 4]

In the chemical formula (4), A²And A¹Independently of each other, bonded to an arbitrary position of the benzene ring and representing a linear, branched or cyclic alkylene group, alkyleneoxy group or direct bond having 1 to 6 carbon atoms, B²And B¹Independently of one another, represents acryloyloxy, methacryloyloxy, acryloylamino or methacryloylamino.

In the sealant composition, the photo radical polymerization initiator having the polymerizable functional group may be composed of a compound represented by the following chemical formula (5).

[ solution 5]

In the chemical formula (5), A²And A¹Independently of each other, bonded to an arbitrary position of the benzene ring and representing a linear, branched or cyclic alkylene group, alkyleneoxy group or direct bond having 1 to 6 carbon atoms, B²And B¹Independently of one another, represents acryloyloxy, methacryloyloxy, acryloylamino or methacryloylamino.

In the sealant composition, the polymeric component has heat-reactive functional groups, and the sealant composition is provided with a heat hardener for crosslinking the heat-reactive functional groups with each other.

In addition, the liquid crystal cell of the present invention has a liquid crystal layer; a pair of substrates sandwiching the liquid crystal layer and facing each other; and a sealing material which is composed of a cured product of the sealing material composition described in any one of the above and is interposed between the pair of substrates so as to surround the liquid crystal layer and be bonded to the pair of substrates, respectively.

In the liquid crystal cell, the first substrate is composed of a first dielectric substrate, and a TFT substrate having a plurality of TFTs (Thin Film transistors) supported by the first dielectric substrate and a plurality of patch electrodes (patch electrodes) electrically connected to the TFTs, the second substrate is composed of a second dielectric substrate and a slit substrate having a slit electrode having a plurality of slits supported by the second dielectric substrate, the liquid crystal layer is interposed between the TFT substrate and the slit substrate, the TFT substrate is disposed so that the side of the patch electrode faces the side of the slit electrode so that the slits are disposed corresponding to the patch electrodes, and the sealing material is interposed between the TFT substrate and the slit substrate.

In the liquid crystal unit, the liquid crystal layer preferably contains a liquid crystal compound containing an isothiocyanate group.

In the liquid crystal cell, the isothiocyanate group-containing liquid crystal compound preferably has a structure represented by any one of the following chemical formulas (6-1) and (6-2).

[ solution 6]

In the chemical formula (6-1) and the chemical formula (6-2), n¹、m²And n²Each of which is an integer of 1 to 5, and H in the phenylene group may be substituted with F or Cl.

In the liquid crystal cell, the TFT substrate and/or the slit substrate may have an alignment film made of a polyimide resin and disposed on the liquid crystal layer side.

A method for manufacturing a liquid crystal cell according to the present invention is the method for manufacturing a liquid crystal cell according to any one of the above, wherein the sealing material is made of a cured product obtained by curing the sealing material composition by irradiating the sealing material composition with light having a wavelength of 450nm or more.

The method for manufacturing the liquid crystal unit comprises the following steps: the sealing material composition according to any one ofclaims 1 to 6 is applied in a frame shape to any one of a TFT substrate having a first dielectric substrate, a plurality of TFTs supported by the first dielectric substrate, and a plurality of patch electrodes electrically connected to the TFTs, or a slit substrate having a second dielectric substrate, and a slit electrode including a plurality of slits supported by the second dielectric substrate; applying a liquid crystal material to the inside of the frame-shaped sealing material composition on the one substrate by an ODF method; irradiating the sealing material composition on the one substrate with light having a wavelength of 450nm or more to temporarily cure the sealing material composition; bonding the one substrate to the other substrate with the sealant composition interposed therebetween; and curing the sealing material composition.

In the method for manufacturing the liquid crystal unit, the liquid crystal material preferably contains a liquid crystal compound containing an isothiocyanate group.

Effects of the invention

According to the present invention, a sealing material composition and the like can be provided which suppresses a decrease in voltage holding ratio in a liquid crystal cell used for a scanning antenna and the like.

Drawings

FIG. 1 is an explanatory view showing a mechanism of forming an impurity having a stable radical from a liquid crystal compound having an isothiocyanate group.

Fig. 2 is a cross-sectional view schematically showing a part of the scanning antenna according toembodiment 1.

Fig. 3 is a plan view schematically showing a TFT substrate provided in the scanning antenna.

Fig. 4 is a plan view schematically showing a slot substrate provided in the scanning antenna.

Fig. 5 is a sectional view schematically showing an antenna element region of the TFT substrate.

Fig. 6 is a plan view schematically showing an antenna element region of the TFT substrate.

Fig. 7 is a cross-sectional view schematically showing an antenna element region of the slot substrate.

Fig. 8 is a cross-sectional view schematically showing a TFT substrate, a liquid crystal layer, and a slit substrate constituting an antenna unit of a scanning antenna.

Fig. 9 is a sectional view schematically showing the structure of a liquid crystal cell.

Fig. 10 is an explanatory view showing a mechanism of generating radicals from the photo radical polymerization initiator.

Fig. 11 is a diagram showing a synthesis procedure of a photopolymerization initiator having a polymerizable functional group.

Fig. 12 is a flowchart showing a procedure of manufacturing a liquid crystal cell by a dropping method.

Detailed Description

[ embodiment 1]

(basic structure of scanning antenna)

The scanning antenna has a beam scanning function capable of changing a beam direction, and has a configuration including a plurality of antenna elements having anisotropy (birefringence) of a liquid crystal material having a large dielectric constant M (∈ M). The scanning antenna controls a voltage applied to the liquid crystal layer of each antenna unit to change an effective dielectric constant M (∈ M) of the liquid crystal layer of each antenna unit, thereby forming a two-dimensional pattern by the plurality of antenna units having different capacitances. In addition, since the dielectric constant of the liquid crystal material has frequency dispersion, the dielectric constant in the microwave band is specifically referred to as "dielectric constant M (∈ M)" in the present specification.

An electromagnetic wave (for example, a microwave) emitted from or received by the scanning antenna is given a phase difference according to the capacitance of each antenna element, and has a strong directivity in a specific direction (beam scanning) according to a two-dimensional pattern formed by a plurality of antenna elements having different capacitances. For example, the electromagnetic wave emitted from the scanning antenna is obtained by: an input electromagnetic wave is incident on each antenna element, and spherical waves obtained as a result of scattering by each antenna element are integrated in consideration of a phase difference given by each antenna element.

Here, a basic configuration of a scanning antenna according to an embodiment of the present invention will be described with reference to fig. 2 and the like. Fig. 2 is a cross-sectional view schematically showing a part of thescanning antenna 1000 according toembodiment 1. Thescanning antenna 1000 according to the present embodiment is a radial line slot antenna (radial slot antenna) in which theslots 57 are arranged concentrically. Fig. 2 schematically shows a part of a cross section along the radial direction from thepower feeding pin 72 provided in the vicinity of the center of the slits arranged in a concentric circle shape. In other embodiments, the arrangement of the slits may be any of various known arrangements (for example, a spiral or a matrix).

Thescanning antenna 1000 mainly includes aTFT substrate 101, aslit substrate 201, a liquid crystal layer LC disposed therebetween, and a conductive reflective plate 65. Thescanning antenna 1000 is configured to transmit and receive microwaves from theTFT substrate 101 side. TheTFT substrate 101 and theslit substrate 201 are disposed so as to face each other with the liquid crystal layer LC interposed therebetween.

TheTFT substrate 101 includes a dielectric substrate (an example of a first dielectric substrate) 1 such as a glass substrate, a plurality ofpatch electrodes 15 and a plurality ofTFTs 10 formed on the liquid crystal layer LC side of thedielectric substrate 1, and an alignment film OM1 formed on the outermost surface of the liquid crystal layer LC side. A gate bus line (not shown) and a source bus line (not shown) are connected to eachTFT 10.

Theslit substrate 201 includes a dielectric substrate (an example of a second dielectric substrate) 51 such as a glass substrate, aslit electrode 55 formed on the liquid crystal layer LC side of thedielectric substrate 51, and an alignment film OM2 formed on the outermost surface of the liquid crystal layer LC side. Theslit electrode 55 includes a plurality ofslits 57.

Thedielectric substrates 1 and 51 used for theTFT substrate 101 and theslit substrate 201 are preferably small in dielectric loss against microwaves, and a plastic substrate other than a glass substrate can be used. The thickness of thedielectric substrates 1 and 51 is not particularly limited, but is preferably 400 μm or less, and more preferably 300 μm or less. The lower limit of the thickness of thedielectric substrates 1 and 51 is not particularly limited as long as the dielectric substrates have a strength that can be tolerated in the manufacturing process and the like.

The reflective conductive plate 65 is disposed to face theslit substrate 201 with the air layer 54 interposed therebetween. In another embodiment, a layer made of a dielectric having a small dielectric constant M against microwaves (for example, a fluororesin such as PTFE (polytetrafluoroethylene)) may be used instead of the air layer 54. In thescanning antenna 1000 of the present embodiment, theslot electrode 55, the reflective conductive plate 65, and thedielectric substrate 51 and the air layer 54 therebetween function as a Waveguide (Waveguide) 301.

Thepatch electrode 15, a portion of theslit electrode 55 including the slit 57 (hereinafter, sometimes referred to as "slitelectrode unit 57U"), and the liquid crystal layer LC therebetween constitute an antenna unit U. In each antenna unit U, one island-shapedpatch electrode 15 faces each of the 1-hole slits 57 (slit electrode units 57U) through the liquid crystal layer LC, and forms a liquid crystal capacitor. In thescanning antenna 1000 of the present embodiment, a plurality of antenna units U are arranged concentrically. In addition, the antenna unit U includes an auxiliary capacitor electrically connected in parallel to the liquid crystal capacitor.

Theslot electrode 55 constitutes an antenna unit U in eachslot electrode unit 57U, and also functions as a wall of the waveguide 301. Therefore, theslit electrode 55 is required to have a function of suppressing transmission of microwaves, and is formed of a relatively thick metal layer. Examples of such a metal layer include a Cu (copper) layer and an Al (aluminum) layer. For example, in order to reduce the microwave of 10GHz to 1/150, the thickness of the Cu layer is set to 3.3 μm or more and the thickness of the Al layer is set to 4.0 μm or more. Further, in order to reduce the microwave of 30GHz to 1/150, the thickness of the Cu layer was set to 1.9 μm or more and the thickness of the Al layer was set to 2.3 μm or more. The upper limit of the thickness of the metal layer constituting theslit electrode 55 is not particularly limited, but when the formation of the alignment film OM2 is considered as described later, it is said that the thinner the metal layer is, the better the thickness is. Further, when a Cu layer is used as the metal layer, there is an advantage that the Cu layer can be thinner than an Al layer. As a method for forming theslit electrode 55, other methods such as a thin film deposition method used in the conventional liquid crystal display device technology, or a method of attaching a metal foil (for example, Cu foil or Al foil) to a substrate may be used. The thickness of the metal layer is set to, for example, 2 μm to 30 μm. When the metal layer is formed by a thin film deposition method, the thickness of the metal layer is set to, for example, 5 μm or less. The reflective conductive plate 65 can be made of, for example, an aluminum plate or a copper plate having a thickness of several mm (millimeters).

Thepatch electrode 15 is not constituted by the waveguide 301 like theslot electrode 55, and is constituted by a metal layer having a smaller thickness than theslot electrode 55. In order to avoid the loss of heat when vibration of free electrons in the vicinity of theslit 57 of theslit electrode 55 induces vibration of free electrons in thepatch electrode 15, the resistance is preferably low. From the viewpoint of mass productivity and the like, an Al layer is preferably used as compared with a Cu layer, and the thickness of the Al layer is preferably 0.5 μm or more and 2 μm or less, for example.

As described inpatent document 1, the arrangement pitch of the antenna units U is set to, for example, λ/4 or less and/or λ/5 or less, when the wavelength of the microwave is λ. The wavelength λ is, for example, 25mm, and the arrangement pitch in this case is, for example, 6.25mm or less and/or 5mm or less.

Thescanning antenna 1000 changes the phase of the microwave excited (re-radiated) by eachpatch electrode 15 by changing the capacitance value of the liquid crystal capacitance of the antenna unit U. Therefore, the liquid crystal layer LC preferably has a large anisotropy (Δ ∈ M) of dielectric constant M (∈ M) against microwaves and a small tan δ M (dielectric tangent against microwaves). For example, a liquid crystal material having a Δ ∈ M of 4 or more and a tan δ M of 0.02 or less (both values are 19 GHz) as described in SID2015DIGEST (pp.824-826) by M. Further, a liquid crystal material having Δ ∈ M of 0.4 or more and tan δ M of 0.04 or less as described inJiugui polymer 55 volume 8 (pp.599-602(2006)) can also be used.

The dielectric constant of a liquid crystal material generally has frequency dispersion, but the dielectric anisotropy Δ ∈ M for microwaves has a positive correlation with the refractive index anisotropy Δ n for visible light. Therefore, a liquid crystal material for an antenna element for microwaves is preferably a material having a large refractive index anisotropy Δ n with respect to visible light. Here, when Δ n (birefringence) for light of 550nm is used as an index, nematic liquid crystal having Δ n of 0.3 or more, preferably 0.4 or more is used for an antenna unit for microwave. The upper limit of Δ n is not particularly limited. The thickness of the liquid crystal layer LC is set to, for example, 1 μm to 500 μm.

Fig. 3 is a plan view schematically showing theTFT substrate 101 provided in thescanning antenna 1000, and fig. 4 is a plan view schematically showing theslit substrate 201 provided in thescanning antenna 1000. For convenience of description, the region of theTFT substrate 101 and the region of theslot substrate 201 corresponding to the antenna unit U are collectively referred to as an "antenna unit region", and the same reference numerals as those of the antenna unit are used as their reference numerals. As shown in fig. 3 and 4, in theTFT substrate 101 and theslot substrate 201, a region divided by the two-dimensionally arranged plurality of antenna element regions U is referred to as a "transmission/reception region R1", and a region other than the transmission/reception region R1 is referred to as a "non-transmission/reception region R2". A terminal portion, a drive circuit, and the like are disposed in the non-transmission/reception region R2.

The transmission/reception region R1 has an annular shape in plan view. The non-transmitting/receiving area R2 includes a first non-transmitting/receiving area R2a located at the center of the transmitting/receiving area R1, and a second non-transmitting/receiving area R2b arranged at the periphery of the transmitting/receiving area R1. The outer diameter of the transmission/reception area R1 is, for example, 200mm to 1,500mm, and is set as appropriate according to the traffic volume and the like.

In the transmission/reception region R1 of theTFT substrate 101, a plurality of gate bus lines GL and a plurality of source bus lines SL supported by thedielectric substrate 1 are provided, and the driving of each antenna element region U is controlled by these lines. Each antenna element region U includes a TFT10 and apatch electrode 15 electrically connected to theTFT 10. The source electrode of the TFT10 is electrically connected to the source bus line SL, and the gate electrode is electrically connected to the gate bus line GL. Further, the drain electrode of the TFT10 is electrically connected to thepatch electrode 15.

In the non-transmission/reception region R2 (the first non-transmission/reception region R2a and the second non-transmission/reception region R2b), a seal region Rs in which a seal material (not shown) is formed so as to surround the transmission/reception region R1 is disposed. The sealing material adheres theTFT substrate 101 and theslit substrate 201 to each other, and has a function of sealing a liquid crystal material (liquid crystal layer LC) between thesesubstrates 101 and 201. Further, the details of the sealing material will be described below.

In the non-transmission/reception region R2, the gate terminal GT, the gate driver GD, the source terminal ST, and the source driver SD are disposed outside the sealed region Rs. Each gate bus line GL is connected to the gate driver GD through a gate terminal portion GT, and each source bus line SL is connected to the source driver SD through a source terminal portion ST. In the present embodiment, the source driver SD and the gate driver GD are both formed on thedielectric substrate 1 of theTFT substrate 101, but one or both of these drivers may be formed on thedielectric substrate 51 of theslit substrate 201.

The non-transmission/reception area R2 is provided with a plurality of transmission terminal units PT. The transmission terminal PT is electrically connected to theslot electrode 55 of theslot substrate 201. In the present embodiment, the transmission terminal portions PT are disposed in both the first non-transmission/reception region R2a and the second non-transmission/reception region R2 b. In another embodiment, the transmission terminal PT may be provided only in any one of the regions. In the present embodiment, the transmission terminal PT is disposed in the sealed region Rs. Therefore, a conductive resin containing conductive particles (conductive beads) is used as the sealing material.

As shown in fig. 4, in theslot substrate 201, theslot electrode 55 is formed on thedielectric substrate 51 over the transmission/reception region R1 and the non-transmission/reception region R2. In fig. 4, the surface of theslit substrate 201 is shown as viewed from the liquid crystal layer LC side, and the alignment film OM2 formed on the outermost surface is removed for convenience of description.

In the transmission/reception region R1 of theslot substrate 201, a plurality ofslots 57 are provided in theslot electrode 55. Theseslits 57 are allocated to the antenna element regions U of theTFT substrate 101 one by one. In the present embodiment, a pair ofslots 57 extending in substantially orthogonal directions are arranged concentrically with respect to the plurality ofslots 57 so as to form a radial line slot antenna. With such a pair ofslots 57, thescanning antenna 1000 can transmit and receive circularly polarized waves.

In the non-transmission/reception region R2 of theslot substrate 201, a plurality of terminal portions IT of theslot electrode 55 are provided. The terminal portion IT is electrically connected to the transmission terminal portion PT of theTFT substrate 101. In the case of the present embodiment, the terminal portion IT is disposed in the seal region Rs, and is electrically connected to the corresponding transmission terminal portion PT by the seal material made of the conductive resin containing the conductive particles (conductive beads) as described above.

In the first non-transmission/reception region R2a, thepower feed pin 72 is provided so as to be disposed at the center of the concentric circle formed by theslit 57. The microwave is supplied to the waveguide 301 composed of theslot electrode 55, the reflection conductive plate 65, and thedielectric substrate 51 by thepower supply pin 72. Further, thepower supply pin 72 is connected to thepower supply device 70. The power feeding method may be either a direct power feeding method or an electromagnetic coupling method, and a known power feeding structure may be employed.

TheTFT substrate 101, theslit substrate 201, and the waveguide 301 will be described in detail below.

(Structure of TFT substrate 101)

Fig. 5 is a sectional view schematically showing the antenna element region U of theTFT substrate 101, and fig. 6 is a plan view schematically showing the antenna element region U of theTFT substrate 101. Fig. 5 and 6 each show a cross-sectional structure of a part of the transmission/reception region R1.

Each antenna element region U of theTFT substrate 101 includes a dielectric substrate (first dielectric substrate) 1, a TFT10 supported by thedielectric substrate 1, a first insulatinglayer 11 covering the TFT10, apatch electrode 15 formed on the first insulatinglayer 11 and electrically connected to the TFT10, a second insulatinglayer 17 covering thepatch electrode 15, and an alignment film OM1 covering the second insulatinglayer 17.

The TFT10 includes agate electrode 3, an island-shapedsemiconductor layer 5, agate insulating layer 4 disposed between thegate electrode 3 and thesemiconductor layer 5, and asource electrode 7S and adrain electrode 7D. The TFT10 of the present embodiment is a channel-etched type having a bottom gate structure. In other embodiments, TFTs having other structures may be used.

Thegate electrode 3 is electrically connected to the gate bus line GL, and a scanning signal is supplied from the gate bus line GL. Thesource electrode 7S is electrically connected to the source bus line SL, and supplies a data signal from the source bus line SL. Thegate electrode 3 and the gate bus line GL may be formed of the same conductive film (gate conductive film). Thesource electrode 7S, thedrain electrode 7D, and the source bus line SL may be formed of the same conductive film (source conductive film). The conductive film for gate and the conductive film for source are formed of, for example, metal films. A layer formed using a conductive film for a gate is sometimes referred to as a "gate metal layer", and a layer formed using a conductive film for a source is sometimes referred to as a "source metal layer".

Thesemiconductor layer 5 is disposed so as to overlap with thegate electrode 3 with thegate insulating layer 4 interposed therebetween. As shown in fig. 5, asource contact layer 6S and a drain contact are formed on the semiconductor layer 5And acontact layer 6D. Thesource contact layer 6S and thedrain contact layer 6D are disposed so as to face both sides of a region (channel region) in thesemiconductor layer 5 in which a channel is formed. In this embodiment, thesemiconductor layer 5 is formed of an intrinsic amorphous silicon (i-a-Si) layer, and thesource contact layer 6S and thedrain contact layer 6D are formed of n⁺Type amorphous silicon (n)⁺a-Si) layer. In other embodiments, thesemiconductor layer 5 may be formed of a polysilicon layer, an oxide semiconductor layer, or the like.

Thesource electrode 7S is provided in contact with thesource contact layer 6S, and is connected to thesemiconductor layer 5 through thesource contact layer 6S. Thedrain electrode 7D is provided in contact with thedrain contact layer 6D, and is connected to thesemiconductor layer 5 through thedrain contact layer 6D.

The first insulatinglayer 11 includes a contact hole CH1 reaching thedrain electrode 7D of theTFT 10.

Thepad electrode 15 is provided on the first insulatinglayer 11 and in the contact hole CH1, and contacts thedrain electrode 7D in thecontact hole CH 1. Thepatch electrode 15 is mainly composed of a metal layer. Thepatch electrode 15 may be a metal electrode formed only of a metal layer. Thepatch electrode 15 may be made of the same material as thesource electrode 7S and thedrain electrode 7D. The thickness of the metal layer in the patch electrode 15 (the thickness of thepatch electrode 15 when thepatch electrode 15 is a metal electrode) may be the same as the thickness of thesource electrode 7S and thedrain electrode 7D, but is preferably larger than these thicknesses. When the thickness of thepatch electrode 15 is large, the transmittance of the electromagnetic wave is suppressed to be low, the sheet resistance of the patch electrode is reduced, and the change of the vibration of the free electrons in the patch electrode into the loss of heat is reduced.

The CS bus lines CL may be formed using the same conductive film as the gate bus lines GL. The CS bus line CL may be disposed so as to overlap thedrain electrode 7D (or an extended portion of thedrain electrode 7D) with thegate insulating layer 4 interposed therebetween, thereby forming the storage capacitor CS having thegate insulating layer 4 as a dielectric layer.

In the present embodiment, thepatch electrode 15 is formed in a layer different from the source metal layer. Therefore, the thickness of the source metal layer and the thickness of thepatch electrode 15 can be controlled independently of each other.

Thepatch electrode 15 may also include a Cu layer or an Al layer as a main layer. The performance of the scanning antenna is related to the resistance of thepatch electrode 15, and the thickness of the main layer is set in such a way that the desired resistance is obtained. Thepatch electrode 15 preferably has a low resistance to such an extent that the vibration of electrons is not hindered. The thickness of the metal layer in thepatch electrode 15 is set to 0.5 μm or more, for example, when the metal layer is formed of an Al layer.

The alignment film OM1 is made of a polyimide resin. The details of the alignment film OM1 will be described later.

TheTFT substrate 101 is manufactured by the following method, for example. First, thedielectric substrate 1 is prepared. As thedielectric substrate 1, for example, a glass substrate, a heat-resistant plastic substrate, or the like can be used. A gate metal layer including thegate electrode 3 and the gate bus line GL is formed on thedielectric substrate 1.

Thegate electrode 3 may be formed integrally with the gate bus line GL. Here, a conductive film (thickness: for example, 50nm to 500 nm) for a gate electrode is formed on thedielectric substrate 1 by sputtering or the like. Next, the gate conductive film is patterned to form thegate electrode 3 and the gate bus line GL. The material of the gate conductive film is not particularly limited, and for example, a film containing a metal such as aluminum (Al), tungsten (W), molybdenum (Mo), tantalum (Ta), chromium (Cr), titanium (Ti), or copper (Cu), an alloy thereof, or a nitride thereof can be used as appropriate. Here, a stacked film in which MoN (thickness: e.g., 50nm), Al (thickness: e.g., 200nm), and MoN (thickness: e.g., 50nm) are stacked in this order is formed as the conductive film for the gate electrode.

Next, thegate insulating layer 4 is formed so as to cover the gate metal layer. Thegate insulating layer 4 can be formed by a CVD (chemical vapor Deposition) method or the like. As thegate insulating layer 4, silicon oxide (SiO) can be suitably used₂) A layer, a silicon nitride (SiNx) layer, a silicon oxynitride (SiOxNy; x > y), silicon oxynitride (SiNxOy; x > y) layers, and the like. Thegate insulating layer 4 may also have a laminated structure. Here, a SiNx layer (thickness: 410nm, for example) is formed as thegate insulating layer 4.

Next, asemiconductor layer 5 and a contact layer are formed on thegate insulating layer 4. Here, an intrinsic amorphous silicon film (thickness: e.g., 125nm) andn⁺an amorphous silicon film of type (thickness: for example, 65nm) is patterned, thereby obtaining an island-shapedsemiconductor layer 5 and a contact layer. The semiconductor film used for thesemiconductor layer 5 is not limited to an amorphous silicon film. For example, an oxide semiconductor layer may be formed as thesemiconductor layer 5. In this case, a contact layer may be provided between thesemiconductor layer 5 and the source and drain electrodes.

Next, a source conductive film (having a thickness of, for example, 50nm to 500 nm) is formed on thegate insulating layer 4 and the contact layer, and patterned to form a source metal layer including thesource electrode 7S, thedrain electrode 7D, and the source bus line SL. At this time, the contact layer is also etched, forming thesource contact layer 6S and thedrain contact layer 6D separated from each other.

The material of the conductive film for a source is not particularly limited, and for example, a film containing a metal such as aluminum (Al), tungsten (W), molybdenum (Mo), tantalum (Ta), chromium (Cr), titanium (Ti), or copper (Cu), an alloy thereof, or a nitride thereof can be used as appropriate. Here, a stacked film in which MoN (thickness: e.g., 30nm), Al (thickness: e.g., 200nm), and MoN (thickness: e.g., 50nm) are stacked in this order is formed as the conductive film for the source.

Here, for example, a conductive film for a source is formed by sputtering, and patterning of the conductive film for a source (source/drain separation) is performed by wet etching. Then, a portion of the contact layer located on a region to be a channel region of thesemiconductor layer 5 is removed by, for example, dry etching to form a gap portion, and the contact layer is separated into thesource contact layer 6S and thedrain contact layer 6D. At this time, the vicinity of the surface of thesemiconductor layer 5 is also etched (overetched) in the gap portion.

Next, the first insulatinglayer 11 is formed so as to cover theTFT 10. In this example, the first insulatinglayer 11 is disposed so as to be in contact with the channel region of thesemiconductor layer 5. Then, a contact hole CH1 reaching thedrain electrode 7D is formed in the first insulatinglayer 11 using a well-known photolithography technique.

The first insulatinglayer 11 may be, for example, silicon oxide (SiO)₂) A film, a silicon nitride (SiNx) film, a silicon oxynitride (SiOxNy; x > y) film, silicon oxynitride (SiNxOy; x > y) film, and the like. Here, the thickness is formed by, for example, CVD methodA SiNx layer with a thickness of, for example, 330nm is used as the first insulatinglayer 11.

Next, a conductive film for a patch is formed over the first insulatinglayer 11 and in the contact hole CH1, and is patterned. Thereby, thepatch electrode 15 is formed in the transmission/reception region R1. In the non-transmitting/receiving region R2, a patch connection portion formed of the same conductive film as the patch electrode 15 (conductive film for patch) is formed. Thepatch electrode 15 is in contact with thedrain electrode 7D within thecontact hole CH 1.

As a material of the conductive film for a patch, the same material as that of the conductive film for a gate or the conductive film for a source can be used. However, the conductive film for a patch is preferably set to be thicker than the conductive film for a gate and the conductive film for a source. The suitable thickness of the conductive film for patch is, for example, 1 μm or more and 30 μm or less. When the thickness is smaller than this, the transmittance of electromagnetic waves becomes about 30%, the sheet resistance becomes 0.03 Ω/sq or more, and a problem of large loss may occur, and when the thickness is larger, a problem of deterioration in patterning property of theslit 57 may occur.

Here, a laminated film (MoN/Al/MoN) in which MoN (thickness: e.g., 50nm), Al (thickness: e.g., 1000nm), and MoN (thickness: e.g., 50nm) are laminated in this order is formed as a conductive film for a patch.

Next, a second insulating layer (thickness: for example, 100nm to 300 nm) 17 is formed on thepatch electrode 15 and the first insulatinglayer 11. The second insulatinglayer 17 is not particularly limited, and for example, silicon oxide (SiO) can be used as appropriate₂) A film, a silicon nitride (SiNx) film, a silicon oxynitride (SiOxNy; x > y) film, silicon oxynitride (SiNxOy; x > y) films, and the like. Here, a SiNx layer, for example, 200nm thick is formed as the second insulatinglayer 17.

Then, the inorganic insulating films (the second insulatinglayer 17, the first insulatinglayer 11, and the gate insulating layer 4) are etched together by, for example, dry etching using a fluorine-based gas. During etching, thepad electrode 15, the source bus line SL, and the gate bus line GL function as an etching stopper. Thereby, a second contact hole reaching the gate bus line GL is formed in the second insulatinglayer 17, the first insulatinglayer 11, and thegate insulating layer 4, and a third contact hole reaching the source bus line SL is formed in the second insulatinglayer 17 and the first insulatinglayer 11. Further, a fourth contact hole reaching the patch connection portion is formed in the second insulatinglayer 17.

Then, a conductive film (having a thickness of 50nm to 200nm) is formed on the second insulatinglayer 17 and in the second contact hole, the third contact hole, and the fourth contact hole by, for example, sputtering. For example, a transparent conductive film such as an ITO (Indium Tin Oxide) film, an IZO (Indium Zinc Oxide) film, or a ZnO film (Zinc Oxide film) can be used as the conductive film. Here, an ITO film having a thickness of, for example, 100nm is used as the conductive film.

Then, the transparent conductive film is patterned to form an upper connection portion for a gate terminal, an upper connection portion for a source terminal, and an upper connection portion for a transmission terminal. The gate terminal upper connection portion, the source terminal upper connection portion, and the transmission terminal upper connection portion protect the electrodes or the wires exposed at the respective terminal portions. Thus, the gate terminal portion GT, the source terminal portion ST, and the transmission terminal portion PT are obtained.

Next, the alignment film OM1 is formed so as to cover the second insulatinglayer 17 and the like. Details of the alignment film OM1 will be described later. Thus, theTFT substrate 101 can be manufactured.

(Structure of slit substrate 201)

Next, the structure of theslit substrate 201 will be described in more detail. Fig. 7 is a cross-sectional view schematically showing the antenna unit region U of theslot substrate 201.

Theslit substrate 201 mainly includes a dielectric substrate (second dielectric substrate) 51, aslit electrode 55 formed on one plate surface (a plate surface facing the liquid crystal layer side, a plate surface facing theTFT substrate 101 side) 51a of thedielectric substrate 51, a third insulatinglayer 58 covering theslit electrode 55, and an alignment film OM2 covering the third insulatinglayer 58.

In the transmission/reception region R1 of theslot substrate 201, a plurality ofslots 57 are formed in the slot electrode 55 (see fig. 3). Theslit 57 is an opening (groove) penetrating theslit electrode 55. In this example, oneslot 57 is allocated to each antenna element region U.

Theslit electrode 55 includes amain layer 55M such as a Cu layer or an Al layer. Theslit electrode 55 may have a laminated structure including amain layer 55M, and anupper layer 55U and alower layer 55L arranged so as to sandwich themain layer 55M. The thickness of themain layer 55M is set in consideration of the skin effect according to the material, and may be, for example, 2 μ M or more and 30 μ M or less. The thickness of themain layer 55M is typically set larger than the thicknesses of theupper layer 55U and thelower layer 55L.

In this example, themain layer 55M is composed of a Cu layer, and theupper layer 55U and thelower layer 55L are composed of a Ti layer. By disposing thelower layer 55L between themain layer 55M and thedielectric substrate 51, the adhesion between theslit electrode 55 and thedielectric substrate 51 can be improved. Further, by providing theupper layer 55U, corrosion of themain layer 55M (e.g., Cu layer) can be suppressed.

A third insulatinglayer 58 is formed on theslit electrode 55 and in theslit 57. The material of the third insulating layer 52 is not particularly limited, and for example, silicon oxide (SiO) can be used as appropriate₂) A film, a silicon nitride (SiNx) film, a silicon oxynitride (SiOxNy; x > y) film, silicon oxynitride (SiNxOy; x > y) films, and the like.

The alignment film OM2 is made of a polyimide resin, similarly to the alignment film OM1 of theTFT substrate 101. Details of the alignment film OM2 will be described later.

In addition, a terminal portion IT (see fig. 4) is provided in the non-transmission/reception region R2 of theslot substrate 201. The terminal portion IT includes a part of theslit electrode 55, a third insulatinglayer 58 covering a part of theslit electrode 55, and an upper connection portion. The third insulatinglayer 58 has an opening (contact hole) reaching a part of theslit electrode 55. The upper connection portion is in contact with a part of theslit electrode 55 within the opening. In the present embodiment, the terminal portion IT is formed of a conductive layer such as an ITO film or an IZO film, and is disposed in the sealing region Rs, and is connected to the transmission terminal portion PT of theTFT substrate 101 by a sealing resin containing conductive particles (e.g., conductive beads such as Au beads).

Theslot substrate 201 is manufactured by, for example, the following method. First, thedielectric substrate 51 is prepared. As thedielectric substrate 51, a substrate having a high transmittance (a low dielectric constant ∈ M and a low dielectric loss tan δ M) against electromagnetic waves, such as a glass substrate or a resin substrate, can be used. Thedielectric substrate 51 is preferably thin in order to suppress attenuation of electromagnetic waves. For example, after forming a component such as theslit electrode 55 on the surface of the glass substrate by a process described later, the glass substrate may be thinned from the back side. Thus, the thickness of the glass substrate can be set to, for example, 500 μm or less. In addition, the dielectric constant ∈ M and the dielectric loss tan δ M of the resin are generally smaller than those of glass. Therefore, when thedielectric substrate 51 is formed of a resin substrate, the thickness thereof is, for example, 3 μm or more and 300 μm or less. As a material of the resin base material, polyimide or the like can be used.

Aslit electrode 55 having a plurality ofslits 57 is obtained by forming a metal film on thedielectric substrate 51 and patterning it. As the metal film, a Cu film (or Al film) having a thickness of 2 μm or more and 5 μm or less may be used. Here, a laminated film in which a Ti film, a Cu film, and a Ti film are laminated in this order is used.

Next, a third insulating layer (thickness: for example, 100nm to 200nm) 58 is formed on theslit electrode 55 and theslit 57. The third insulating layer 52 here is made of silicon oxide (SiO)₂) A membrane.

Then, in the non-transmission/reception region R2, an opening (contact hole) reaching a part of theslit electrode 55 is formed in the third insulatinglayer 58.

Next, a transparent conductive film is formed over the third insulatinglayer 58 and in the opening of the third insulatinglayer 58, and is patterned, whereby an upper connection portion which is in contact with a part of theslit electrode 55 is formed in the opening, and a terminal portion IT for connection to the transmission terminal portion PT of theTFT substrate 101 is obtained.

Subsequently, an alignment film OM2 is formed so as to cover the third insulatinglayer 58. Details of the alignment film OM2 will be described later. Thus, theslot substrate 201 can be manufactured.

(Structure of waveguide 301)

The waveguide 301 is configured to face theslot electrode 55 with thedielectric substrate 51 interposed therebetween by the reflective conductive plate 65. The reflective conductive plate 65 is disposed to face the rear surface of thedielectric substrate 51 with the air layer 54 interposed therebetween. The reflective conductive plate 65 constitutes a wall of the waveguide 301, and therefore preferably has a thickness of 3 times or more, preferably 5 times or more, the skin depth. The reflective conductive plate 65 can be made of, for example, an aluminum plate, a copper plate, or the like having a thickness of several mm, which is manufactured by cutting.

For example, when thescanning antenna 1000 transmits a signal, the waveguide 301 guides the microwave supplied from thepower feeding pin 72 disposed at the center of the plurality of antenna units U arranged concentrically to each other so as to radially spread outward. When the microwave moves through the waveguide 301, the microwave is cut by theslots 57 of the antenna units U, and an electric field is generated by the principle of the so-called slot antenna, and electric charges are induced in theslot electrode 55 by the action of the electric field (that is, the microwave is converted into vibration of free electrons in the slot electrode 55). In each antenna unit U, the phase of the vibration of the free electrons induced in thepatch electrode 15 is controlled by changing the capacitance value of the liquid crystal capacitance by controlling the orientation of the liquid crystal. When thepatch electrode 15 induces electric charges, an electric field is generated (that is, vibration of free electrons in theslit electrode 55 moves to vibration of free electrons in the patch electrode 15), and microwaves (radio waves) are oscillated from thepatch electrode 15 of each antenna unit U to the outside of theTFT substrate 101. The azimuth of the beam is controlled by combining microwaves (radio waves) oscillated from the antenna elements U with different phases.

In another embodiment, the waveguide may have a two-layer structure including an upper layer and a lower layer. At this time, the microwaves supplied by the feeding pins first move in the lower layer in such a manner as to spread radially from the center to the outside, then rise to the upper layer at the outer wall portion of the lower layer, and move in the upper layer in such a manner as to converge from the outside to the center. By providing such a two-layer structure, the microwave can be easily distributed uniformly in each antenna unit U.

(alignment film OM (OM1, OM2))

The alignment films OM1 and OM2 (hereinafter, these may be collectively referred to as "alignment film OM") used for theTFT substrate 101 and theslit substrate 201 according to the present embodiment are formed of, for example, a polyamic acid represented by the following chemical formula (7) which is imidized as shown by the following chemical formula (8) and subjected to an alignment treatment such as a rubbing treatment. The alignment film OM performs an alignment treatment to align the liquid crystal compound in a predetermined direction.

[ solution 7]

[ solution 8]

In the above chemical formulae (7) and (8), p is an arbitrary natural number

And (4) counting. In chemical formulas (7) and (8), X has a structure represented by the following chemical formulas (9-1) to (9-16).

[ solution 9]

In chemical formulas (7) and (8), Y has a structure represented by the following chemical formulas (10-1) to (10-24).

[ solution 10]

In chemical formulas (7) and (8), Z represents a side chain. The structure of Z is not particularly limited as long as the object of the present invention is not impaired. In addition, Z may be absent. In the absence of Z in the chemical formula (7) and the chemical formula (8), the bonding groups of the chemical formulas (10-1) to (10-24) may be at any two positions.

The imidization of the polyamic acid represented by the above chemical formula (7) is performed by, for example, subjecting the polyamic acid to a heat treatment at a high temperature (for example, 200 to 250 ℃). Further, for example, a chemical imidization method using acetic anhydride or the like as a dehydrating agent and pyridine or the like as a catalyst can be used. The imidization ratio of the polyimide represented by the above chemical formula (8) is not particularly limited as long as the object of the present invention is not impaired, and for example, 5 is preferableMore than 0 percent. If the imidization ratio is less than 50%, a thiourethane bond insoluble to the liquid crystal material or other bonds (-C) are easily formed due to the reaction of an isothiocyanate group and a carboxyl group in the liquid crystal material₆H₄-NH-CS-O-)。

The alignment film OM may be a horizontal alignment film having an alignment direction horizontal to the substrate surface, or a vertical alignment film having an alignment direction vertical to the substrate surface.

The method of polymerizing polyamic acid is not particularly limited, and a known method can be used. The polyamic acid is suitably dissolved in an organic solvent and is prepared as a liquid or gel-like composition (alignment agent) having fluidity.

In the present embodiment, the alignment film OM (alignment films OM1, OM2) is formed on the surfaces of both theTFT substrate 101 and theslit substrate 201, but in other embodiments, the alignment film OM may be formed only on the surface of either theTFT substrate 101 or theslit substrate 201.

When forming the alignment film OM, first, an alignment agent having fluidity in an uncured state containing the polyamic acid represented by the chemical formula (7) is applied to the surfaces of thesubstrates 101 and 201 using a coater. The coated product is first subjected to a pre-baking (e.g., a heat treatment at 80 ℃ for 2 minutes) and then to a main baking (e.g., a heat treatment at 210 ℃ for 10 minutes). Then, the coated material after the normal baking is subjected to rubbing treatment, thereby obtaining an alignment film OM having alignment properties for aligning the liquid crystal compound in a predetermined direction. The polyamic acid is imidized at the time of pre-baking or at the time of main baking.

(liquid Crystal layer LC (liquid Crystal Compound))

As a liquid crystal material (liquid crystal compound) constituting the liquid crystal layer, an isothiocyanate group-containing liquid crystal compound having a large dielectric anisotropy (Δ ∈) (for example, 10 or more) is used. Examples of the isothiocyanate group-containing liquid crystal compound include compounds represented by the following chemical formula (6-1) and chemical formula (6-2).

[ solution 11]

In the chemical formula (6-1) and the chemical formula (6-2), n¹、m²And n²Each of which is an integer of 1 to 5, and H in the phenylene group may be substituted with F or Cl.

The liquid crystal material may contain a liquid crystal compound other than the isothiocyanate group-containing liquid crystal compound, as long as the object of the present invention is not impaired.

(antenna Unit U)

Fig. 8 is a cross-sectional view schematically showing theTFT substrate 101, the liquid crystal layer LC, and theslit substrate 201 of the antenna unit U constituting thescanning antenna 1000. As shown in fig. 8, in the antenna unit U, the island-shapedpatch electrode 15 of theTFT substrate 101 and the hole-shaped (groove-shaped) slit 57 (slit electrode unit 57U) provided in theslit electrode 55 of theslit substrate 201 face each other so as to sandwich the liquid crystal layer LC. Thescanning antenna 1000 includes a liquid crystal cell C having a liquid crystal layer LC, and a pair ofTFT substrates 101 and aslit substrate 201 sandwiching the liquid crystal layer LC and having alignment films OM1 and OM2 on the surfaces on the liquid crystal layer LC side. In the present specification, the antenna unit U is configured to include onepatch electrode 15 and a slot electrode 55 (slot electrode unit 57U) in which at least oneslot 57 is arranged corresponding to thepatch electrode 15.

(sealing Material)

Fig. 9 is a sectional view schematically showing the structure of the liquid crystal cell C. A seal material S is disposed between theTFT substrate 101 and theslit substrate 201 constituting the liquid crystal cell C so as to surround the liquid crystal layer LC. The sealing material S adheres to theTFT substrate 101 and theslit substrate 201, respectively, and has a function of bonding theTFT substrate 101 and theslit substrate 201 to each other. TheTFT substrate 101 and theslit substrate 201 form a pair of substrates facing each other with the liquid crystal layer LC interposed therebetween.

The sealing material S is composed of a cured product of a sealing material composition containing a curable resin. The sealant composition mainly includes a photo radical polymerization initiator and a curable resin (polymerization component).

The photo radical polymerization initiator is composed of a compound that generates radicals when irradiated with light having a wavelength of 450nm or more. As such a photo radical polymerization initiator, a compound containing a structure represented by the following chemical formula (1) can be cited.

[ solution 12]

In the chemical formula (1), R represents a substituent bonded to an arbitrary position of the benzene ring. As will be described later, when the photo radical polymerization initiator having the structure represented by the above chemical formula (1) absorbs light having a wavelength of 450nm or more, the bond between the carbon atom and the sulfur atom of the methylene group in the above chemical formula (1) is cleaved to generate a radical.

The R is composed of, for example, a polymerizable functional group represented by the following chemical formula (2).

[ solution 13]

-A¹-B¹ (2)

In the above chemical formula (2), A¹Represents a linear, branched or cyclic alkylene group having 1 to 6 carbon atoms, an alkyleneoxy group or a direct bond, B¹Represents an acryloyloxy group, a methacryloyloxy group, an acryloylamino group or a methacryloylamino group.

The photo radical polymerization initiator having the polymerizable functional group is composed of, for example, a compound represented by the following chemical formula (3).

[ solution 14]

In the above chemical formula (3), n is 0 or 1, Ar represents an arylene group, and the H atom of each functional group may be substituted with an alkyl group, a halogen group, a hydroxyl group or an alkoxy group. In addition, A²And A¹Independently of each other, represents a linear, branched or cyclic subunit having 1 to 6 carbon atomsAlkyl, alkyleneoxy or a direct bond, B²And B¹Independently of one another, represents acryloyloxy, methacryloyloxy, acryloylamino or methacryloylamino.

In the above chemical formula (3), specific examples of Ar (arylene) include phenylene, naphthyl, and ethynyl.

Here, a mechanism of generating radicals from the photo radical polymerization initiator represented by the above chemical formula (3) will be described with reference to fig. 10. Fig. 10 is an explanatory view showing a mechanism of generating radicals from the photo radical polymerization initiator. As shown in fig. 10, when light (light having a wavelength of 450nm or more) is irradiated to the compound represented by chemical formula (3) (photo radical polymerization initiator), the bond between the carbon atom and the sulfur atom of the methylene group in chemical formula (3) is cleaved, and two compounds (3-1), (3-2) each having a radical are obtained. In this way, radicals are generated from the photo radical polymerization initiator.

The photo radical polymerization initiator having the polymerizable functional group is composed of, for example, a compound represented by the following chemical formula (4).

[ solution 15]

In the above chemical formula (4), A²And A¹Independently of each other, bonded to an arbitrary position of the benzene ring and representing a linear, branched or cyclic alkylene group, alkyleneoxy group or direct bond having 1 to 6 carbon atoms, B²And B¹Independently of one another, represents acryloyloxy, methacryloyloxy, acryloylamino or methacryloylamino.

The photo radical polymerization initiator having the polymerizable functional group is composed of a compound represented by the following chemical formula (5).

[ solution 16]

In the above chemical formula (5), A²And A¹Independently of each other, bonded to an arbitrary position of the benzene ring and representing a linear, branched or cyclic alkylene group, alkyleneoxy group or direct bond having 1 to 6 carbon atoms, B²And B¹Independently of one another, represents acryloyloxy, methacryloyloxy, acryloylamino or methacryloylamino.

Specific examples of the compound represented by the above chemical formula (3) include a compound represented by the following chemical formula (17).

[ solution 17]

Specific examples of the compound represented by the above chemical formula (4) include a compound represented by the following chemical formula (18).

[ solution 18]

In addition, as a specific example of the compound represented by the above chemical formula (5), for example, a compound represented by the following chemical formula (19) can be cited.

[ solution 19]

Here, an example of synthesizing the photo radical polymerization initiator having a polymerizable functional group represented by the chemical formula (17) will be described with reference to fig. 11. Fig. 11 is a diagram showing a synthesis procedure of a photopolymerization initiator having a polymerizable functional group. 3.8g (10mmol) of the compound represented by the formula (b-1) (molecular weight: 378) and the compound represented by the formula (b-2) were mixed by stirring at room temperature (23 ℃) for two hours in a nitrogen atmosphere1.2g (10mmol) of substance (molecular weight: 116), Pd (PPh)₃)₂Cl₂9g (13mmol), CuI 2g (10mmol), and Triethylamine (TEA)30 mL. Next, an appropriate amount of benzene was added to the mixed solution, and then, the mixed solution was filtered. Then, the filtered mixture was washed with an aqueous sodium sulfate solution, water and a saturated saline solution. Using a column chromatograph (normal phase column, developing solvent is n-hexane: CHCl)₃The washed mixed solution was purified at 5:1(v/v)), to obtain 2.85g (7.8mmol, yield 78%) of a compound represented by the formula (b-3) (molecular weight: 366).

2.6g (7mmol) of the compound of the formula (b-3) (molecular weight: 366), 1.8g (10mmol) of N-bromosuccinimide (NBS), and 1.6g (5mmol) of Benzoyl Peroxide (BPO) were dissolved in 40mL of benzene, and the resulting solution was refluxed at 80 ℃ for 10 hours under a nitrogen atmosphere. Then, the mixture was filtered, and the filtered solution was washed with saturated saline. Thereafter, a column chromatograph (normal phase column, developing solvent n-hexane: CHCl) was used₃The washed solution was purified at 5:1(v/v)) to obtain 1.87g (4.2mmol, yield 60%) of a compound represented by the formula (b-4) (molecular weight: 455).

As shown in FIG. 11, 1.8g (4mmol) of the compound of formula (b-4) (molecular weight: 445), 1.8g (10mmol) of the compound of formula (b-5) (molecular weight: 180), and K₂CO₃1.4g (10mmol) was dissolved in 40mL of acetone, and the resulting solution was refluxed at 80 ℃ for 20 hours under a nitrogen atmosphere. Thereafter, the solvent was removed, and the residue was dissolved in 150mL of benzene, and the resulting solution was washed with a saturated saline solution. Using a column chromatograph (normal phase column, developing solvent is n-hexane: CHCl)₃The washed solution was purified at 3:1(v/v)) to obtain 2.0g (3.68mmol, yield 92%) of the target compound represented by chemical formula (17) (molecular weight: 544). In this way, the compound of chemical formula (17) can be synthesized.

The photo radical polymerization initiator may also be used alone or in combination of two or more.

In the photo radical polymerization initiator as described above, the radical can be generated by absorbing visible light (visible light having a wavelength of 450nm or more) on a longer wavelength side than the wavelength absorbed by the isothiocyanate group-containing liquid crystal compound so as not to undergo photocleavage of the isothiocyanate group-containing liquid crystal compound shown in fig. 1.

As the curable resin, a compound (polymerization component) containing a polymerizable functional group that can be polymerized by a radical generated by a photo radical polymerization initiator is used. As such a curable resin, for example, a resin having a (meth) acryloyl group and/or epoxy group can be suitably used from the viewpoint of a rapid curing reaction when a sealant composition is applied by a dropping method (ODF method) in a liquid crystal cell production process, and good adhesion. Examples of such a curable resin include (meth) acrylate and epoxy resin. These resins may be used alone or in combination of two or more. In the present specification, the term (meth) acrylic acid means acrylic acid or methacrylic acid.

The (meth) acrylate is not particularly limited as long as the object of the present invention is not impaired, and examples thereof include: urethane (meth) acrylates having a urethane bond, epoxy (meth) acrylates derived from a compound having a glycidyl group and (meth) acrylic acid, and the like.

The urethane (meth) acrylate is not particularly limited as long as the object of the present invention is not impaired, and examples thereof include: and derivatives of a reactive compound obtained by addition reaction of a diisocyanate such as isophorone diisocyanate with an isocyanate such as acrylic acid or hydroxyethyl acrylate. These derivatives may be chain-extended with caprolactone, polyhydric alcohol, or the like. Examples of commercially available products include: the trade names "U-122P", "U-340P", "U-4 HA", "U-1084A" (manufactured by NOVEL CENTRAL CHEMICAL INDUSTRIAL Co., Ltd.), and "KRM 7595", "KRM 7610", "KRM 7619" (manufactured by DALULURON UCB Co., Ltd.).

The epoxy (meth) acrylate is not particularly limited as long as the object of the present invention is not impaired, and examples thereof include: epoxy resins such as bisphenol a type epoxy resins and propylene glycol diglycidyl ether, and epoxy (meth) acrylates derived from (meth) acrylic acid. Further, examples of commercially available products include: the trade names "EA-1020", "EA-6320", "EA-5520" (manufactured by Nippon Mekko chemical Co., Ltd.), and "Epoxy ester (Epoxy Resin)70 PA", "Epoxy ester (Epoxy Resin) 3002A" (manufactured by Kyoho chemical Co., Ltd.).

Examples of other (meth) acrylates include: methyl methacrylate, tetrahydrofurfuryl methacrylate, benzyl methacrylate, isobornyl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, (poly) ethylene glycol dimethacrylate, 1, 4-butanediol dimethacrylate, 1, 6-hexanediol dimethacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, glycerol dimethacrylate, and the like.

The epoxy resin is not particularly limited as long as the object of the present invention is not impaired, and examples thereof include: phenol novolac type epoxy resins, cresol novolac type epoxy resins, biphenol novolac type epoxy resins, trisphenol novolac type epoxy resins, dicyclopentadiene novolac type epoxy resins, bisphenol a type epoxy resins, bisphenol F type epoxy resins, 2' -diallylbisphenol a type epoxy resins, bisphenol S type epoxy resins, hydrogenated bisphenol a type epoxy resins, propylene oxide adduct bisphenol a type epoxy resins, biphenyl type epoxy resins, naphthalene type epoxy resins, resorcinol type epoxy resins, glycidylamine and the like.

Among the above-mentioned epoxy resins, commercially available products include, for example, a phenyl novolak type epoxy resin having a trade name of "NC-3000S" (manufactured by Nippon Kagaku Co., Ltd.), a trisphenol novolak type epoxy resin having a trade name of "EPPN-501H" or "EPPN-501H" (manufactured by Nippon Kagaku Co., Ltd.), a dicyclopentadiene novolak type epoxy resin having a trade name of "NC-7000L" (manufactured by Nippon Kagaku Co., Ltd.), a bisphenol A type epoxy resin having a trade name of "Epiclon S840" or "Epiclon 850 CRP" (manufactured by Dainippon ink chemical industry Co., Ltd.), a bisphenol F type epoxy resin having a trade name of "Epicoat 807" (manufactured by Nippon epoxy resin Co., Ltd.), a trade name of "Epiclon 830" (manufactured by Dainippon ink chemical industry Co., Ltd.), the 2, 2' -diallylbisphenol A-type Epoxy Resin may be referred to by the trade name "RE 310 NM" (manufactured by Nippon chemical Co., Ltd.), the hydrogenated bisphenol A-type Epoxy Resin may be referred to by the trade name "Epiclon 7015" (manufactured by Dainippon ink chemical industry Co., Ltd.), the propylene oxide-added bisphenol A-type Epoxy Resin may be referred to by the trade name "Epoxy ester (Epoxy Resin) 3002A" (manufactured by Kyoho chemical Co., Ltd.), the biphenyl-type Epoxy Resin may be referred to by the trade names "Epicoat YX-4000H" and "YL 6121H" (manufactured by Nippon Epoxy Resin Co., Ltd.), the naphthalene-type Epoxy Resin may be referred to by the trade name "Epiclon HP-4032" (manufactured by Dainippon ink chemical industry Co., Ltd.), the resorcinol-type Epoxy Resin may be referred to by the trade name "Denacol EX-201" (manufactured by Long chemical industry Co., Ltd.), examples of the glycidylamines include "Epiclon 430" (manufactured by Dainippon ink chemical industries, Ltd.) and "Epicoat 630" (manufactured by Nippon epoxy resins, Ltd.).

In addition, in the sealant composition, an epoxy/(meth) acrylic resin having at least one (meth) acrylic group and at least one epoxy group in one molecule can be suitably used as the curable resin (polymerization component). Examples of such epoxy/(meth) acrylic resins include: a compound obtained by reacting a part of epoxy groups of the epoxy resin with (meth) acrylic acid in the presence of a basic catalyst according to a conventional method; a compound obtained by reacting 1/2 moles of a (meth) acrylic monomer having a hydroxyl group with 1 mole of a bifunctional or higher isocyanate and then reacting 1/2 moles of glycidol; and compounds obtained by reacting glycidol with (meth) acrylates having an isocyanate group. Examples of the commercially available epoxy/(meth) acrylic resin include "UVAC 1561" (manufactured by UCB corp.).

The sealing material composition may contain a thermosetting agent, a silane coupling agent, a filler, and the like in addition to the photo radical polymerization initiator and the like.

The thermosetting agent is added to the sealant composition together with a curable resin (polymer component) having a thermally reactive functional group (e.g., epoxy group) (e.g., epoxy resin, epoxy/(meth) acrylic resin) when the sealant composition contains the curable resin. The thermosetting agent is used to react a thermally reactive functional group in a curable resin (polymer component) by heating and to crosslink the resin, and has a function of improving the adhesiveness, moisture resistance, and the like of the cured sealant composition (i.e., the sealant S).

The thermal curing agent is not particularly limited as long as the object of the present invention is not impaired, and for example, when the sealant composition is applied by a dropping method (ODF method) in the production process of the liquid crystal cell, it is preferable to contain an amine and/or thiol group having excellent low-temperature reactivity in order to cure the sealant composition at a curing temperature of 100 to 120 ℃. Such a thermosetting agent is not particularly limited as long as the object of the present invention is not impaired, and examples thereof include: hydrazide compounds such as 1, 3-bis [ hydrazinocarbonylethyl-5-isopropylhydantoin, butanamide, adipic acid dihydrazide and the like; dicyandiamide, guanidine derivatives, 1-cyanoethyl-2-phenylimidazole, N- [2- (2-methyl-1-imidazolyl) ethyl ] urea, 2, 4-diamino-6- [2 ' -methylimidazolyl- (1 ') ] -ethyl s-triazine, N ' -bis (2-methyl-1-imidazolylethyl) urea, N ' - (2-methyl-1-imidazolylethyl) -adipamide, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-imidazoline-2-thiol, 2-2 ' -thiodiethylthiol, addition products of various amines to epoxy resins, and the like. These may be used alone or in combination of two or more.

The silane coupling agent has a function of improving adhesion between the cured sealing material composition (i.e., the sealing material S) and the substrate. The silane coupling agent is not particularly limited as long as the object of the present invention is not impaired, and for example, a silane coupling agent composed of the following compounds can be suitably used from the viewpoint of having an excellent effect of improving adhesion to a substrate or the like and preventing the outflow into a liquid crystal material by chemical bonding with a curable resin: gamma-aminopropyltrimethoxysilane, gamma-mercaptopropyltrimethoxysilane, gamma-glycidoxypropyltrimethoxysilane, gamma-isocyanatopropyltrimethoxysilane, or the like, or an imidazolesilane compound having a structure in which an imidazole skeleton and an alkoxysilyl group are bonded via a spacer. These silane coupling agents may also be used alone or in combination of two or more.

The filler may be added to the sealing material composition for the purpose of improving adhesiveness by the stress dispersion effect, improving linear expansion coefficient, and the like, as long as the object of the present invention is not impaired. Examples of such fillers include: inorganic fillers such as silica, diatomaceous earth, alumina, zinc oxide, iron oxide, magnesium oxide, tin oxide, titanium oxide, magnesium hydroxide, aluminum hydroxide, magnesium carbonate, barium sulfate, gypsum, calcium silicate, talc, glass beads, sericite, activated clay, bentonite, aluminum nitride, and silicon nitride. These may be used alone or in combination of two or more.

The sealing material composition may further contain other components such as a thermal radical polymerization initiator, a gelling agent, and a sensitizer as necessary.

Examples of the thermal radical polymerization initiator include thermal radical polymerization initiators composed of azo compounds, organic peroxides, and the like. Examples of the azo compound include: 2, 2' -azobis (2, 4-dimethylvaleronitrile), azobisisobutyronitrile, and the like. Examples of the organic peroxide include: benzoyl peroxide, ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides, peroxyesters, diacyl peroxides, peroxydicarbonates, and the like.

Further, as the sealant composition, a solvent-free composition is basically used.

(method of manufacturing scanning antenna)

The method for manufacturing the scanning antenna (method for manufacturing the liquid crystal cell C) includes the steps of: theTFT substrate 101 and theslit substrate 201 are bonded to each other with a sealing material S, and a liquid crystal layer LC is injected between theTFT substrate 101 and theslit substrate 201. As a method of injecting the liquid crystal material, a dropping method (ODF method) can be cited. Here, a method for manufacturing the liquid crystal cell C by the dropping method will be described.

Fig. 11 is a flowchart showing a procedure of manufacturing the liquid crystal cell C by the dropping method. As shown in fig. 11, first, a sealing material composition is applied in a frame shape by a seal dispenser to either of theTFT substrate 101 and the slit substrate 201 (here, the TFT substrate 101) prepared in advance (step 1). The sealing material composition contains a photo radical polymerization initiator (e.g., a compound represented by chemical formula (17)), a curable resin (e.g., an epoxy/(meth) acrylic resin), a thermosetting agent, and the like. Next, a liquid crystal material (a liquid crystal compound containing a sulfur-containing isocyanate group) was applied (dropped) to the substrate (the TFT substrate 101) by the ODF method (step 2). Then, the sealing material composition is irradiated with light having a wavelength of 450nm or more, thereby temporarily curing the sealing material composition (step 3). At this time, radicals are generated by the photo radical polymerization initiator, and the curable resin is temporarily cured by the radicals.

Next, the substrate (TFT substrate 101) and another substrate (slit substrate 201) are bonded to each other with the temporarily cured sealing material composition interposed therebetween (step 4). Then, the sealant composition is heated and is cured by a crosslinking reaction between the heat-reactive functional group (epoxy group) and the heat-reactive functional group (epoxy group), thereby bonding theTFT substrate 101 and theslit substrate 201 to each other. In this way, the liquid crystal cell C can be produced by the dropping method.

After the liquid crystal cell C is manufactured by the liquid crystal dropping method as described above, the reflective conductive plate 65 is attached to the cell side so as to face the opposite surface of the slit substrate 201 (second dielectric substrate 51) through the dielectric (air layer) 54 as appropriate. The scanning antenna of the present embodiment is manufactured through such steps.

In the above-described embodiment, the sealing material composition is applied to the liquid crystal cell for the scanning antenna, but the sealing material composition may be applied to other liquid crystal cells for devices (for example, a liquid crystal cell for a liquid crystal lens which uses liquid crystal as an optical element and controls a focal length by an applied voltage) as long as the object of the present invention is not impaired.

[ examples ]

The present invention will be described in more detail below with reference to examples. In addition, the present invention is not limited to these examples in any way.

[ example 1]

(preparation of liquid Crystal cell for scanning antenna)

A TFT substrate having the same basic structure as theTFT substrate 101 included in the liquid crystal cell of thescanning antenna 1000 and a slit substrate having the same basic structure as theslit substrate 201 included in the liquid crystal cell are prepared. The alignment film of the TFT substrate and the alignment film of the slit substrate are both formed using an alignment agent described later.

As the orientation agent, an orientation agent obtained by dissolving the polyamic acid represented by the chemical formula (7) in an organic solvent is used. In addition, X in the chemical formula (7) is the chemical formula (9-5), Y is the chemical formula (10-10), and Z is not provided. As the organic solvent, NMP (N-methyl-2-pyrrolidone) was used.

When forming the alignment films on the TFT substrate and the slit substrate, the alignment agent is first applied by an ink jet method, and a coating film made of the alignment agent is formed on each substrate. Then, each coating film on each substrate was heated at a temperature of 80 ℃ for 2 minutes (pre-baking), and then each coating film was heated at a temperature of 210 ℃ for 10 minutes (main baking).

Then, rubbing treatment (alignment treatment) is performed on each coating film on each substrate, whereby an alignment film made of the alignment agent is formed on each surface of the TFT substrate and the slit substrate.

A sealing material composition having photo-curing properties and thermosetting properties, which will be described later, is drawn in a frame shape on the surface (alignment film side) of the TFT substrate using a seal dispenser. Then, the sealing material composition is temporarily cured by irradiating light (wavelength: 450nm to 600nm) while cutting light of 450nm or less with a cut filter. Simultaneously, a liquid crystal material containing the isothiocyanate group-containing liquid crystal compounds represented by the above chemical formulas (6-1) and (6-2) was dropped into a frame made of the sealing material composition by an ODF method (nematic-isotropic phase transition temperature (Tni): 140 ℃). The Tni of the liquid crystal material is obtained by analyzing the thermal behavior of the liquid crystal material using a thermal characteristic measuring apparatus (manufactured by Mettler-Toledo corporation), a Differential Scanning Calorimeter (DSC), or the like.

After the liquid crystal material was sufficiently spread in the frame of the sealing material, the TFT substrate and the slit substrate were bonded so as to sandwich the sealing material, and in this state, the sealing material was heated at 130 ℃ for 40 minutes to be completely cured, and the liquid crystal material was subjected to a reorientation treatment. Thus, a liquid crystal cell of example 1 was produced.

As the sealing material composition, a visible light-curable composition containing the following components in the following ratios was used: 3% by mass of a compound represented by the following chemical formula (17) as a photo radical polymerization initiator generating radicals under light of 450nm or more, 30% by mass of a (meth) acrylic monomer, 20% by mass of an epoxy monomer, 15% by mass of an epoxy monomer curing agent (thermal curing agent), 2% by mass of a silane coupling agent, and 30% by mass of an inorganic filler.

[ example 2]

A sealant composition was prepared in the same manner as in example 1 except that 3 mass% of the compound represented by the above chemical formula (20) (which generates radicals under light of 450nm or more) was used instead of the photo radical polymerization initiator in example 1, and a liquid crystal cell of example 2 was produced from the sealant composition in the same manner as in example 1.

[ solution 20]

[ comparative example 1]

A liquid crystal cell of comparative example 1 was produced in the same manner as in example 1 except that a sealant composition was prepared in the same manner as in example 1 except that 3 mass% of Irgacure-OXE01 (1, 2-octanedione 1- [4- (phenylthio) -2- (O-benzoyl oxime), manufactured by BASF Japan ltd.) was used instead of the photoradical polymerization initiator of example 1, and that 365nm ultraviolet light was irradiated instead of visible light during temporary curing of the sealant composition.

(high temperature light irradiation test)

The following high-temperature light irradiation test was performed on each of the liquid crystal cells of examples 1 and 2 and comparative example 1. The liquid crystal cell was left to stand (aged) for 500 hours in a thermostatic bath having an interior exposed to light from a fluorescent lamp provided outside through a window glass and a temperature condition of 90 ℃, and the Voltage Holding Ratio (VHR) of the liquid crystal cell and the residual DC Voltage (rDC) were measured on the left and right sides of the cell (at the start of the test (0 hour) and 500 hours after the start of the test). The voltage holding ratio was measured under the conditions of 1V and 70 ℃ using a VHR measurement system of model 6254 (manufactured by Toyo technology Co., Ltd.). The measurement results are shown in Table 1. The residual DC voltage (V) was measured by a flicker (flicker) elimination method after applying a DC (Direct Current) bias voltage of 2V to the liquid crystal cell in an oven at a temperature of 40 ℃ for 2 hours. The results are shown in Table 1.

[ Table 1]

In the liquid crystal cell of example 1, the compound represented by the above chemical formula (17) was used as a photo radical polymerization initiator of the sealant composition. The compound has an acryloyl group as a polymerizable functional group, and absorbs light of 450nm or more to generate a radical. As shown in table 1, VHR of the liquid crystal cell of example 1 was 88% and rDC was 0.05V or less at the start of the test (0 hour). Further, after the liquid crystal cell of example 1 was left alone for 500 hours (after aging), the VHR was 60% and rDC was 0.2V or less.

In the liquid crystal cell of example 2, the compound represented by the above chemical formula (20) was used as a photo radical polymerization initiator of the sealant composition. This compound absorbs light of 450nm or more to generate radicals, but unlike the photo radical polymerization initiator used in example 1, it does not have a polymerizable functional group. As shown in table 1, VHR of the liquid crystal cell of example 2 was 89% at the start of the test (0 hour), and rDC was 0.05V or less. However, after the liquid crystal cell of example 2 was left for 500 hours, the VHR was reduced to 40%, and rDC became about 0.4V.

In the liquid crystal cell of comparative example 1, a compound (trade name "Irgacure-OXE 01") that absorbs ultraviolet light to generate radicals was used as a polymerization initiator for the sealant composition. As shown in table 1, the VHR of the liquid crystal cell of comparative example 1 was as low as 55% at the start of the test (0 hour), and rDC was as high as 0.3V or more. In this case, it is presumed that a part of the ultraviolet light irradiated for photo-curing the sealing material deteriorates the liquid crystal material (isothiocyanate group-containing liquid crystal compound). Further, VHR of the liquid crystal cell of comparative example 1 after 500 hours of standing was reduced to 15% or less, and rDC was increased to about 0.7V or more. This is presumably because unreacted polymerization initiator elutes into the liquid crystal layer, and the eluted polymerization initiator receives light to generate radicals.

As described above, in examples 1 and 2, the polymerizable component (e.g., (meth) acrylic monomer) in the sealant composition was polymerized by light (visible light) having a long wavelength (wavelength: 450nm or more) that did not deteriorate the liquid crystal material (isothiocyanate group-containing liquid crystal compound). In particular, in example 1, since the photo radical polymerization initiator has a polymerizable functional group, the photo radical polymerization initiator is polymerized together with the polymerization component. Therefore, in example 1, it was confirmed that the VHR at the start of the test (0 hour) was high and the decrease in VHR with the passage of time was small, while the unreacted photo radical polymerization initiator was prevented from remaining in a free state in the sealing material.

Further, example 2 has a higher VHR and a smaller rDC compared to comparative example 1 in which radicals are generated by ultraviolet light, but results of VHR and rDC are inferior compared to example 1 having a polymerizable functional group. In this case, it is estimated that unreacted photo radical polymerization initiator is eluted into the liquid crystal layer with the passage of time, and the eluted photo radical polymerization initiator generates radicals by receiving light, resulting in a decrease in VHR and an increase in rDC.

[ example 3]

A sealant composition was prepared in the same manner as in example 1 except that 3 mass% of the compound represented by the above chemical formula (18) (which generates radicals under light of 450nm or more) was used instead of the photo-radical polymerization initiator in example 1, and a liquid crystal cell of example 3 was produced from the sealant composition in the same manner as in example 1.

[ example 4]

A sealant composition was prepared in the same manner as in example 1 except that 3 mass% of the compound represented by the above chemical formula (21) (which generates radicals under light of 450nm or more) was used instead of the photo-radical polymerization initiator in example 1, and a liquid crystal cell of example 4 was produced from the sealant composition in the same manner as in example 1.

[ solution 21]

(high temperature light irradiation test)

The liquid crystal cells of examples 3 and 4 were subjected to the high-temperature light irradiation test, and VHR and residual DC voltage (rDC) of the liquid crystal cells at the start of the test (0 hours) and 500 hours after the start of the test were measured in the same manner as in example 1 and the like. The results are shown in Table 2.

[ Table 2]

In the liquid crystal cell of example 3, the compound represented by the above chemical formula (18) was used as a photo radical polymerization initiator of the sealant composition. The compound has a methacryloyl group as a polymerizable functional group, and absorbs light of 450nm or more to generate a radical. In the liquid crystal cell of example 3, the effect of improving reliability was confirmed by maintaining the VHR value high and rDC low as in example 1.

In the liquid crystal cell of example 4, as the photo radical polymerization initiator of the sealing material composition, the compound represented by the above chemical formula (21) was used. This compound absorbs light of 450nm or more to generate radicals, and as in example 2, does not have a polymerizable functional group. In the liquid crystal cell of example 4, as shown in table 2, VHR at the start of the test (0 hour) was 84%, and rDC was 0.05V or less. However, in the liquid crystal cell of example 4, VHR after 500 hours of standing was as low as 46%, and rDC became 0.43V.

[ example 5]

A sealant composition was prepared in the same manner as in example 1 except that 3 mass% of a compound represented by the following chemical formula (19) (which generates radicals under light of 450nm or more) was used instead of the photo-radical polymerization initiator in example 1, and a liquid crystal cell of example 5 was produced from the sealant composition in the same manner as in example 1.

[ example 6]

A sealant composition was prepared in the same manner as in example 1 except that 3 mass% of a compound represented by the following chemical formula (22) (which generates radicals under light of 450nm or more) was used instead of the photo-radical polymerization initiator in example 1, and a liquid crystal cell of example 6 was produced from the sealant composition in the same manner as in example 1.

[ solution 22]

(high temperature light irradiation test)

The liquid crystal cells of examples 5 and 6 were subjected to the high-temperature light irradiation test described above, and VHR and residual DC voltage (rDC) of the liquid crystal cells at the start of the test (0 th) and 500 hours after the start of the test were measured in the same manner as in example 1 and the like. The results are shown in Table 3.

[ Table 3]

In the liquid crystal cell of example 5, the compound represented by the above chemical formula (19) was used as a photo radical polymerization initiator of the sealant composition. The compound has a methacryloyl group as a polymerizable functional group and absorbs light of 450nm or more to generate a radical. As shown in table 3, in the liquid crystal cell of example 5, the effect of improving reliability was confirmed by maintaining the VHR value high and rDC low as in example 1.

In the liquid crystal cell of example 6, the compound represented by the above chemical formula (22) was used as a photo radical polymerization initiator of the sealing material composition. This compound absorbs light of 450nm or more to generate radicals, but does not have a polymerizable functional group as in example 2. In the liquid crystal cell of example 5, as shown in table 3, VHR at the start of the test (0 hour) was 86%, and rDC was 0.05V% or less. However, in the liquid crystal cell of example 6, VHR after 500 hours of standing was as low as 41%, and rDC became 0.40V.

Description of the reference numerals

1: dielectric substrate (first dielectric substrate)

3: gate electrode

4: gate insulating layer

5: semiconductor layer

6D: drain contact layer

6S: source contact layer

7D: drain electrode

7S: source electrode

10：TFT

11: a first insulating layer

15: patch electrode

17: a second insulating layer

51: dielectric substrate (second dielectric substrate)

55: gap electrode

55L: lower layer

55M: main layer

55U: upper layer of

57: gap

57U: gap electrode unit

58: third electrode

70: power supply device

72: power supply pin

101: TFT substrate

201: gap substrate

1000: scanning antenna

U: antenna unit (antenna unit area)

CH 1: contact hole

LC: liquid crystal layer

C: liquid crystal cell

GD: gate driver

GL: gate bus

GT: grid terminal part

SD: source driver

SL: source bus

ST: source terminal part

PT: transmission terminal part

R1: transmit-receive area

R2: non-transmitting/receiving area

Rs: sealing area

S: sealing material

OM, OM1, OM 2: alignment film

C: liquid crystal cell

Claims (4)

1. A sealing material composition characterized by comprising: a photo-radical polymerization initiator that generates radicals when irradiated with light having a wavelength of 450nm or more; and a polymerization component containing a polymerizable functional group polymerizable by a radical, wherein the photo radical polymerization initiator has a structure represented by the following chemical formula (1),

in the chemical formula (1), R represents a substituent bonded to an arbitrary position of a benzene ring,

in the chemical formula (1), R is composed of a polymerizable functional group represented by the following chemical formula (2),

-A¹-B¹ (2)

in the chemical formula (2), A¹Represents a linear, branched or cyclic alkylene group having 1 to 6 carbon atoms, an alkyleneoxy group or a direct bond, B¹Represents an acryloyloxy group, a methacryloyloxy group, an acryloylamino group or a methacryloylamino group,

the photo radical polymerization initiator having the polymerizable functional group is composed of a compound represented by the following chemical formula (3),

in the chemical formula (3), n is 0 or 1, Ar represents an arylene group, the H atom of each functional group is substituted or not substituted by an alkyl group, a halogen group, a hydroxyl group or an alkoxy group, and A is²And A¹Independently of each other, represents a linear, branched or cyclic alkylene group, alkyleneoxy group or a direct bond having 1 to 6 carbon atoms, B²And B¹Independently of one another, represents acryloyloxy, methacryloyloxy, acryloylamino or methacryloylamino.

2. A sealing material composition characterized by comprising: a photo-radical polymerization initiator that generates radicals when irradiated with light having a wavelength of 450nm or more; and a polymerization component containing a polymerizable functional group polymerizable by a radical, wherein the photo radical polymerization initiator has a structure represented by the following chemical formula (1),

in the chemical formula (1), R represents a substituent bonded to an arbitrary position of a benzene ring,

in the chemical formula (1), R is composed of a polymerizable functional group represented by the following chemical formula (2),

-A¹-B¹ (2)

in the chemical formula (2), A¹Represents a linear, branched or cyclic alkylene group having 1 to 6 carbon atoms, an alkyleneoxy group or a direct bond, B¹Represents an acryloyloxy group, a methacryloyloxy group, an acryloylamino group or a methacryloylamino group, and the photo radical polymerization initiator having the polymerizable functional group is composed of a compound represented by the following chemical formula (4),

in the chemical formula (4), A²And A¹Independently of each other, bonded to an arbitrary position of the benzene ring and representing a linear, branched or cyclic alkylene group, alkyleneoxy group or direct bond having 1 to 6 carbon atoms, B²And B¹Independently of one another, represents acryloyloxy, methacryloyloxy, acryloylamino or methacryloylamino.

3. A sealing material composition characterized by comprising: a photo-radical polymerization initiator that generates radicals when irradiated with light having a wavelength of 450nm or more; and a polymerization component containing a polymerizable functional group polymerizable by a radical, wherein the photo radical polymerization initiator has a structure represented by the following chemical formula (1),

in the chemical formula (1), R represents a substituent bonded to an arbitrary position of a benzene ring,

in the chemical formula (1), R is composed of a polymerizable functional group represented by the following chemical formula (2),

-A¹-B¹ (2)

in the chemical formula (2), A¹Represents a linear, branched or cyclic alkylene group having 1 to 6 carbon atoms, an alkyleneoxy group or a direct bond, B¹Represents an acryloyloxy group, a methacryloyloxy group, an acryloylamino group or a methacryloylamino group, the photo radical polymerization initiator having the polymerizable functional group being composed of a compound represented by the following chemical formula (5),

in the chemical formula (5), A²And A¹Independently of each other, bonded to an arbitrary position of the benzene ring and representing a linear, branched or cyclic alkylene group, alkyleneoxy group or direct bond having 1 to 6 carbon atoms, B²And B¹Independently of one another, represents acryloyloxy, methacryloyloxy, acryloylamino or methacryloylamino.

4. The sealing material composition according to any one of claims 1 to 3, wherein: the polymeric component has a thermally reactive functional group,

the sealing material composition is provided with a heat hardener for crosslinking the heat-reactive functional groups with each other.

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